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Helmholtz double layer

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Helmholtz double layer

[′helm‚hōlts ¦dəb·əl ′lā·ər]
(physics)
An electrical double layer of positive and negative charges one molecule thick which occurs at a surface where two bodies of different materials are in contact, or at the surface of a metal or other substance capable of existing in solution as ions and immersed in a dissociating solvent.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive
On the basis of type, the market is segmented into electrical double layer capacitors (EDLC), pseudo-capacitors, and hybrid capacitors.
Among his topics are the origin of charge at interfaces and structure of the electrical double layer, Van der Waals attraction, the adsorption of surfactants at the liquid/liquid interface, polymers and polymeric surfactants and their association, and the flocculation of sterically stabilized dispersions.
gave attention and conducted preliminary studies on inducing particle-wall effect in electroosmotic flow; Peng then experimentally found that the higher the zeta potential of the electrical double layer around the surface of the polarizable solid, the more particles agglomerated; demonstrating the feasibility of using micronanoparticle manipulation to induce electroosmosis.
Mojid MA, Cho H (2008) Wetting solution and electrical double layer contributions to bulk electrical conductivity of sand clay mixtures.
This text deals with the electrical double layer at the electrode-solution interface in aqueous chemical solutions.
The charging process at a solid/liquid interface is assumed to arise from the presence of an electrical double layer, which in commercial polymers may appear by the presence of additives and impurities.
Consequently, an excess of charges is built up near the electrode surface, thus forming an electrical double layer with thickness equal to the Debye screening length [lambda] = [([epsilon]RT/2[z.sup.2][Fc.sub.o]).sup.1/2], determined by a thermal Boltzmann distribution of counter-ions in the screened electric field generated by the surface charges.
Thus an electrical double layer builds up around the particle surface.
As a background to this topic it is necessary to consider the structure of the inner part of the electrical double layer. The electrical double layer consists of 2 parts, the inner part described as the Stern layer, which can be envisaged as 2 layers of water (approximately 5.5 A thick) at the clay solution interface, in which exchangeable cations or counterions are predominately held, and the outer part or diffuse double layer (Verwey and Overbeek 1948).
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